Commit | Line | Data |
96449e8e |
1 | package SQL::Abstract; # see doc at end of file |
2 | |
9d9d5bd6 |
3 | use Carp (); |
312d830b |
4 | use List::Util (); |
5 | use Scalar::Util (); |
a82e41dc |
6 | use Module::Runtime qw(use_module); |
3a9aca02 |
7 | use Moo; |
8b9b83ae |
8 | use namespace::clean; |
96449e8e |
9 | |
64b9e432 |
10 | our $VERSION = '1.72'; |
7479e27e |
11 | |
a82e41dc |
12 | $VERSION = eval $VERSION; |
96449e8e |
13 | |
14 | sub belch (@) { |
15 | my($func) = (caller(1))[3]; |
9d9d5bd6 |
16 | Carp::carp "[$func] Warning: ", @_; |
96449e8e |
17 | } |
18 | |
19 | sub puke (@) { |
20 | my($func) = (caller(1))[3]; |
9d9d5bd6 |
21 | Carp::croak "[$func] Fatal: ", @_; |
96449e8e |
22 | } |
23 | |
a82e41dc |
24 | has converter => (is => 'lazy', clearer => 'clear_converter'); |
96449e8e |
25 | |
3a9aca02 |
26 | has case => ( |
27 | is => 'ro', coerce => sub { $_[0] eq 'lower' ? 'lower' : undef } |
28 | ); |
96449e8e |
29 | |
3a9aca02 |
30 | has logic => ( |
31 | is => 'ro', coerce => sub { uc($_[0]) }, default => sub { 'OR' } |
32 | ); |
96449e8e |
33 | |
3a9aca02 |
34 | has bindtype => ( |
35 | is => 'ro', default => sub { 'normal' } |
36 | ); |
96449e8e |
37 | |
3a9aca02 |
38 | has cmp => (is => 'ro', default => sub { '=' }); |
96449e8e |
39 | |
3a9aca02 |
40 | has sqltrue => (is => 'ro', default => sub { '1=1' }); |
41 | has sqlfalse => (is => 'ro', default => sub { '0=1' }); |
42 | |
43 | has special_ops => (is => 'ro', default => sub { [] }); |
44 | has unary_ops => (is => 'ro', default => sub { [] }); |
59f23b3d |
45 | |
a82e41dc |
46 | # FIXME |
47 | # need to guard against ()'s in column names too, but this will break tons of |
48 | # hacks... ideas anyone? |
8f57728a |
49 | |
3a9aca02 |
50 | has injection_guard => ( |
51 | is => 'ro', |
52 | default => sub { |
53 | qr/ |
54 | \; |
55 | | |
56 | ^ \s* go \s |
57 | /xmi; |
58 | } |
59 | ); |
60 | |
29a3e5dc |
61 | has renderer => (is => 'lazy', clearer => 'clear_renderer'); |
3a9aca02 |
62 | |
29a3e5dc |
63 | has name_sep => ( |
64 | is => 'rw', default => sub { '.' }, |
a82e41dc |
65 | trigger => sub { |
66 | $_[0]->clear_renderer; |
67 | $_[0]->clear_converter; |
68 | }, |
29a3e5dc |
69 | ); |
3a9aca02 |
70 | |
29a3e5dc |
71 | has quote_char => ( |
72 | is => 'rw', |
a82e41dc |
73 | trigger => sub { |
74 | $_[0]->clear_renderer; |
75 | $_[0]->clear_converter; |
76 | }, |
29a3e5dc |
77 | ); |
a9bb5c4c |
78 | |
62d17764 |
79 | has collapse_aliases => ( |
80 | is => 'ro', |
81 | default => sub { 0 } |
82 | ); |
83 | |
a82e41dc |
84 | has always_quote => ( |
85 | is => 'rw', default => sub { 1 }, |
86 | trigger => sub { |
87 | $_[0]->clear_renderer; |
88 | $_[0]->clear_converter; |
89 | }, |
90 | ); |
3a9aca02 |
91 | |
92 | has convert => (is => 'ro'); |
93 | |
94 | has array_datatypes => (is => 'ro'); |
95 | |
a82e41dc |
96 | has converter_class => ( |
dfaa9684 |
97 | is => 'rw', lazy => 1, builder => '_build_converter_class', |
98 | trigger => sub { shift->clear_converter }, |
a82e41dc |
99 | ); |
100 | |
dfaa9684 |
101 | sub _build_converter_class { |
102 | use_module('SQL::Abstract::Converter') |
103 | } |
104 | |
a82e41dc |
105 | has renderer_class => ( |
dfaa9684 |
106 | is => 'rw', lazy => 1, builder => '_build_renderer_class', |
107 | trigger => sub { shift->clear_renderer }, |
a82e41dc |
108 | ); |
109 | |
dfaa9684 |
110 | sub _build_renderer_class { |
111 | use_module('Data::Query::Renderer::SQL::Naive') |
112 | } |
113 | |
a82e41dc |
114 | sub _converter_args { |
115 | my ($self) = @_; |
116 | Scalar::Util::weaken($self); |
117 | +{ |
118 | lower_case => $self->case, |
119 | default_logic => $self->logic, |
120 | bind_meta => not($self->bindtype eq 'normal'), |
121 | identifier_sep => $self->name_sep, |
122 | (map +($_ => $self->$_), qw( |
123 | cmp sqltrue sqlfalse injection_guard convert array_datatypes |
124 | )), |
125 | special_ops => [ |
126 | map { |
127 | my $sub = $_->{handler}; |
128 | +{ |
129 | %$_, |
130 | handler => sub { $self->$sub(@_) } |
131 | } |
132 | } @{$self->special_ops} |
133 | ], |
134 | renderer_will_quote => ( |
135 | defined($self->quote_char) and $self->always_quote |
136 | ), |
137 | } |
138 | } |
139 | |
140 | sub _build_converter { |
141 | my ($self) = @_; |
dfaa9684 |
142 | $self->converter_class->new($self->_converter_args); |
a82e41dc |
143 | } |
144 | |
145 | sub _renderer_args { |
3a9aca02 |
146 | my ($self) = @_; |
3a9aca02 |
147 | my ($chars); |
148 | for ($self->quote_char) { |
149 | $chars = defined() ? (ref() ? $_ : [$_]) : ['','']; |
150 | } |
a82e41dc |
151 | +{ |
3a9aca02 |
152 | quote_chars => $chars, always_quote => $self->always_quote, |
153 | identifier_sep => $self->name_sep, |
62d17764 |
154 | collapse_aliases => $self->collapse_aliases, |
3a9aca02 |
155 | ($self->case ? (lc_keywords => 1) : ()), # always 'lower' if it exists |
a82e41dc |
156 | }; |
157 | } |
158 | |
159 | sub _build_renderer { |
160 | my ($self) = @_; |
dfaa9684 |
161 | $self->renderer_class->new($self->_renderer_args); |
b6251592 |
162 | } |
96449e8e |
163 | |
8f57728a |
164 | sub _render_dq { |
165 | my ($self, $dq) = @_; |
9057306b |
166 | if (!$dq) { |
167 | return ''; |
168 | } |
3a9aca02 |
169 | my ($sql, @bind) = @{$self->renderer->render($dq)}; |
b4951847 |
170 | wantarray ? |
171 | ($self->{bindtype} eq 'normal' |
172 | ? ($sql, map $_->{value}, @bind) |
a420b11f |
173 | : ($sql, map [ $_->{value_meta}, $_->{value} ], @bind) |
b4951847 |
174 | ) |
175 | : $sql; |
176 | } |
177 | |
a9bb5c4c |
178 | sub _render_sqla { |
179 | my ($self, $type, @args) = @_; |
a82e41dc |
180 | $self->_render_dq($self->converter->${\"_${type}_to_dq"}(@args)); |
170e6c33 |
181 | } |
182 | |
a9bb5c4c |
183 | sub insert { shift->_render_sqla(insert => @_) } |
fe3ae272 |
184 | |
a9bb5c4c |
185 | sub update { shift->_render_sqla(update => @_) } |
9057306b |
186 | |
a9bb5c4c |
187 | sub select { shift->_render_sqla(select => @_) } |
9057306b |
188 | |
a9bb5c4c |
189 | sub delete { shift->_render_sqla(delete => @_) } |
96449e8e |
190 | |
96449e8e |
191 | sub where { |
192 | my ($self, $where, $order) = @_; |
193 | |
1d6b8d4d |
194 | my $sql = ''; |
195 | my @bind; |
196 | |
96449e8e |
197 | # where ? |
1d6b8d4d |
198 | ($sql, @bind) = $self->_recurse_where($where) if defined($where); |
96449e8e |
199 | $sql = $sql ? $self->_sqlcase(' where ') . "( $sql )" : ''; |
200 | |
201 | # order by? |
202 | if ($order) { |
203 | $sql .= $self->_order_by($order); |
204 | } |
205 | |
9d48860e |
206 | return wantarray ? ($sql, @bind) : $sql; |
96449e8e |
207 | } |
208 | |
a9bb5c4c |
209 | sub _recurse_where { shift->_render_sqla(where => @_) } |
d4e889af |
210 | |
96449e8e |
211 | sub _order_by { |
212 | my ($self, $arg) = @_; |
a82e41dc |
213 | if (my $dq = $self->converter->_order_by_to_dq($arg)) { |
b4951847 |
214 | # SQLA generates ' ORDER BY foo'. The hilarity. |
215 | wantarray |
216 | ? do { my @r = $self->_render_dq($dq); $r[0] = ' '.$r[0]; @r } |
217 | : ' '.$self->_render_dq($dq); |
218 | } else { |
219 | ''; |
f267b646 |
220 | } |
f267b646 |
221 | } |
222 | |
955e77ca |
223 | # highly optimized, as it's called way too often |
96449e8e |
224 | sub _quote { |
955e77ca |
225 | # my ($self, $label) = @_; |
96449e8e |
226 | |
955e77ca |
227 | return '' unless defined $_[1]; |
955e77ca |
228 | return ${$_[1]} if ref($_[1]) eq 'SCALAR'; |
96449e8e |
229 | |
b6251592 |
230 | unless ($_[0]->{quote_char}) { |
170e6c33 |
231 | $_[0]->_assert_pass_injection_guard($_[1]); |
b6251592 |
232 | return $_[1]; |
233 | } |
96449e8e |
234 | |
07d7c35c |
235 | my $qref = ref $_[0]->{quote_char}; |
955e77ca |
236 | my ($l, $r); |
07d7c35c |
237 | if (!$qref) { |
238 | ($l, $r) = ( $_[0]->{quote_char}, $_[0]->{quote_char} ); |
955e77ca |
239 | } |
07d7c35c |
240 | elsif ($qref eq 'ARRAY') { |
241 | ($l, $r) = @{$_[0]->{quote_char}}; |
955e77ca |
242 | } |
243 | else { |
244 | puke "Unsupported quote_char format: $_[0]->{quote_char}"; |
245 | } |
96449e8e |
246 | |
07d7c35c |
247 | # parts containing * are naturally unquoted |
248 | return join( $_[0]->{name_sep}||'', map |
955e77ca |
249 | { $_ eq '*' ? $_ : $l . $_ . $r } |
250 | ( $_[0]->{name_sep} ? split (/\Q$_[0]->{name_sep}\E/, $_[1] ) : $_[1] ) |
251 | ); |
96449e8e |
252 | } |
253 | |
a82e41dc |
254 | sub _assert_pass_injection_guard { |
255 | if ($_[1] =~ $_[0]->{injection_guard}) { |
256 | my $class = ref $_[0]; |
257 | die "Possible SQL injection attempt '$_[1]'. If this is indeed a part of the |
258 | " |
259 | . "desired SQL use literal SQL ( \'...' or \[ '...' ] ) or supply your own |
260 | " |
261 | . "{injection_guard} attribute to ${class}->new()" |
262 | } |
263 | } |
96449e8e |
264 | |
265 | # Conversion, if applicable |
266 | sub _convert ($) { |
07d7c35c |
267 | #my ($self, $arg) = @_; |
96449e8e |
268 | |
269 | # LDNOTE : modified the previous implementation below because |
270 | # it was not consistent : the first "return" is always an array, |
271 | # the second "return" is context-dependent. Anyway, _convert |
9d48860e |
272 | # seems always used with just a single argument, so make it a |
96449e8e |
273 | # scalar function. |
274 | # return @_ unless $self->{convert}; |
275 | # my $conv = $self->_sqlcase($self->{convert}); |
276 | # my @ret = map { $conv.'('.$_.')' } @_; |
277 | # return wantarray ? @ret : $ret[0]; |
07d7c35c |
278 | if ($_[0]->{convert}) { |
279 | return $_[0]->_sqlcase($_[0]->{convert}) .'(' . $_[1] . ')'; |
96449e8e |
280 | } |
07d7c35c |
281 | return $_[1]; |
96449e8e |
282 | } |
283 | |
284 | # And bindtype |
285 | sub _bindtype (@) { |
07d7c35c |
286 | #my ($self, $col, @vals) = @_; |
96449e8e |
287 | |
9d48860e |
288 | #LDNOTE : changed original implementation below because it did not make |
96449e8e |
289 | # sense when bindtype eq 'columns' and @vals > 1. |
290 | # return $self->{bindtype} eq 'columns' ? [ $col, @vals ] : @vals; |
291 | |
07d7c35c |
292 | # called often - tighten code |
293 | return $_[0]->{bindtype} eq 'columns' |
294 | ? map {[$_[1], $_]} @_[2 .. $#_] |
295 | : @_[2 .. $#_] |
296 | ; |
96449e8e |
297 | } |
298 | |
fe3ae272 |
299 | # Dies if any element of @bind is not in [colname => value] format |
300 | # if bindtype is 'columns'. |
301 | sub _assert_bindval_matches_bindtype { |
c94a6c93 |
302 | # my ($self, @bind) = @_; |
303 | my $self = shift; |
fe3ae272 |
304 | if ($self->{bindtype} eq 'columns') { |
c94a6c93 |
305 | for (@_) { |
306 | if (!defined $_ || ref($_) ne 'ARRAY' || @$_ != 2) { |
3a06278c |
307 | puke "bindtype 'columns' selected, you need to pass: [column_name => bind_value]" |
fe3ae272 |
308 | } |
309 | } |
310 | } |
311 | } |
312 | |
96449e8e |
313 | # Fix SQL case, if so requested |
314 | sub _sqlcase { |
96449e8e |
315 | # LDNOTE: if $self->{case} is true, then it contains 'lower', so we |
316 | # don't touch the argument ... crooked logic, but let's not change it! |
07d7c35c |
317 | return $_[0]->{case} ? $_[1] : uc($_[1]); |
96449e8e |
318 | } |
319 | |
96449e8e |
320 | sub values { |
321 | my $self = shift; |
322 | my $data = shift || return; |
323 | puke "Argument to ", __PACKAGE__, "->values must be a \\%hash" |
324 | unless ref $data eq 'HASH'; |
bab725ce |
325 | |
326 | my @all_bind; |
327 | foreach my $k ( sort keys %$data ) { |
328 | my $v = $data->{$k}; |
5cf3969e |
329 | local our $Cur_Col_Meta = $k; |
a9bb5c4c |
330 | my ($sql, @bind) = $self->_render_sqla( |
331 | mutation_rhs => $v |
5cf3969e |
332 | ); |
333 | push @all_bind, @bind; |
bab725ce |
334 | } |
335 | |
336 | return @all_bind; |
96449e8e |
337 | } |
338 | |
339 | sub generate { |
340 | my $self = shift; |
341 | |
342 | my(@sql, @sqlq, @sqlv); |
343 | |
344 | for (@_) { |
345 | my $ref = ref $_; |
346 | if ($ref eq 'HASH') { |
347 | for my $k (sort keys %$_) { |
348 | my $v = $_->{$k}; |
349 | my $r = ref $v; |
350 | my $label = $self->_quote($k); |
351 | if ($r eq 'ARRAY') { |
fe3ae272 |
352 | # literal SQL with bind |
353 | my ($sql, @bind) = @$v; |
354 | $self->_assert_bindval_matches_bindtype(@bind); |
96449e8e |
355 | push @sqlq, "$label = $sql"; |
fe3ae272 |
356 | push @sqlv, @bind; |
96449e8e |
357 | } elsif ($r eq 'SCALAR') { |
fe3ae272 |
358 | # literal SQL without bind |
96449e8e |
359 | push @sqlq, "$label = $$v"; |
9d48860e |
360 | } else { |
96449e8e |
361 | push @sqlq, "$label = ?"; |
362 | push @sqlv, $self->_bindtype($k, $v); |
363 | } |
364 | } |
365 | push @sql, $self->_sqlcase('set'), join ', ', @sqlq; |
366 | } elsif ($ref eq 'ARRAY') { |
367 | # unlike insert(), assume these are ONLY the column names, i.e. for SQL |
368 | for my $v (@$_) { |
369 | my $r = ref $v; |
fe3ae272 |
370 | if ($r eq 'ARRAY') { # literal SQL with bind |
371 | my ($sql, @bind) = @$v; |
372 | $self->_assert_bindval_matches_bindtype(@bind); |
373 | push @sqlq, $sql; |
374 | push @sqlv, @bind; |
375 | } elsif ($r eq 'SCALAR') { # literal SQL without bind |
96449e8e |
376 | # embedded literal SQL |
377 | push @sqlq, $$v; |
9d48860e |
378 | } else { |
96449e8e |
379 | push @sqlq, '?'; |
380 | push @sqlv, $v; |
381 | } |
382 | } |
383 | push @sql, '(' . join(', ', @sqlq) . ')'; |
384 | } elsif ($ref eq 'SCALAR') { |
385 | # literal SQL |
386 | push @sql, $$_; |
387 | } else { |
388 | # strings get case twiddled |
389 | push @sql, $self->_sqlcase($_); |
390 | } |
391 | } |
392 | |
393 | my $sql = join ' ', @sql; |
394 | |
395 | # this is pretty tricky |
396 | # if ask for an array, return ($stmt, @bind) |
397 | # otherwise, s/?/shift @sqlv/ to put it inline |
398 | if (wantarray) { |
399 | return ($sql, @sqlv); |
400 | } else { |
401 | 1 while $sql =~ s/\?/my $d = shift(@sqlv); |
402 | ref $d ? $d->[1] : $d/e; |
403 | return $sql; |
404 | } |
405 | } |
406 | |
96449e8e |
407 | 1; |
408 | |
409 | |
96449e8e |
410 | __END__ |
32eab2da |
411 | |
412 | =head1 NAME |
413 | |
414 | SQL::Abstract - Generate SQL from Perl data structures |
415 | |
416 | =head1 SYNOPSIS |
417 | |
418 | use SQL::Abstract; |
419 | |
420 | my $sql = SQL::Abstract->new; |
421 | |
422 | my($stmt, @bind) = $sql->select($table, \@fields, \%where, \@order); |
423 | |
424 | my($stmt, @bind) = $sql->insert($table, \%fieldvals || \@values); |
425 | |
426 | my($stmt, @bind) = $sql->update($table, \%fieldvals, \%where); |
427 | |
428 | my($stmt, @bind) = $sql->delete($table, \%where); |
429 | |
430 | # Then, use these in your DBI statements |
431 | my $sth = $dbh->prepare($stmt); |
432 | $sth->execute(@bind); |
433 | |
434 | # Just generate the WHERE clause |
abe72f94 |
435 | my($stmt, @bind) = $sql->where(\%where, \@order); |
32eab2da |
436 | |
437 | # Return values in the same order, for hashed queries |
438 | # See PERFORMANCE section for more details |
439 | my @bind = $sql->values(\%fieldvals); |
440 | |
441 | =head1 DESCRIPTION |
442 | |
443 | This module was inspired by the excellent L<DBIx::Abstract>. |
444 | However, in using that module I found that what I really wanted |
445 | to do was generate SQL, but still retain complete control over my |
446 | statement handles and use the DBI interface. So, I set out to |
447 | create an abstract SQL generation module. |
448 | |
449 | While based on the concepts used by L<DBIx::Abstract>, there are |
450 | several important differences, especially when it comes to WHERE |
451 | clauses. I have modified the concepts used to make the SQL easier |
452 | to generate from Perl data structures and, IMO, more intuitive. |
453 | The underlying idea is for this module to do what you mean, based |
454 | on the data structures you provide it. The big advantage is that |
455 | you don't have to modify your code every time your data changes, |
456 | as this module figures it out. |
457 | |
458 | To begin with, an SQL INSERT is as easy as just specifying a hash |
459 | of C<key=value> pairs: |
460 | |
461 | my %data = ( |
462 | name => 'Jimbo Bobson', |
463 | phone => '123-456-7890', |
464 | address => '42 Sister Lane', |
465 | city => 'St. Louis', |
466 | state => 'Louisiana', |
467 | ); |
468 | |
469 | The SQL can then be generated with this: |
470 | |
471 | my($stmt, @bind) = $sql->insert('people', \%data); |
472 | |
473 | Which would give you something like this: |
474 | |
475 | $stmt = "INSERT INTO people |
476 | (address, city, name, phone, state) |
477 | VALUES (?, ?, ?, ?, ?)"; |
478 | @bind = ('42 Sister Lane', 'St. Louis', 'Jimbo Bobson', |
479 | '123-456-7890', 'Louisiana'); |
480 | |
481 | These are then used directly in your DBI code: |
482 | |
483 | my $sth = $dbh->prepare($stmt); |
484 | $sth->execute(@bind); |
485 | |
96449e8e |
486 | =head2 Inserting and Updating Arrays |
487 | |
488 | If your database has array types (like for example Postgres), |
489 | activate the special option C<< array_datatypes => 1 >> |
9d48860e |
490 | when creating the C<SQL::Abstract> object. |
96449e8e |
491 | Then you may use an arrayref to insert and update database array types: |
492 | |
493 | my $sql = SQL::Abstract->new(array_datatypes => 1); |
494 | my %data = ( |
495 | planets => [qw/Mercury Venus Earth Mars/] |
496 | ); |
9d48860e |
497 | |
96449e8e |
498 | my($stmt, @bind) = $sql->insert('solar_system', \%data); |
499 | |
500 | This results in: |
501 | |
502 | $stmt = "INSERT INTO solar_system (planets) VALUES (?)" |
503 | |
504 | @bind = (['Mercury', 'Venus', 'Earth', 'Mars']); |
505 | |
506 | |
507 | =head2 Inserting and Updating SQL |
508 | |
509 | In order to apply SQL functions to elements of your C<%data> you may |
510 | specify a reference to an arrayref for the given hash value. For example, |
511 | if you need to execute the Oracle C<to_date> function on a value, you can |
512 | say something like this: |
32eab2da |
513 | |
514 | my %data = ( |
515 | name => 'Bill', |
96449e8e |
516 | date_entered => \["to_date(?,'MM/DD/YYYY')", "03/02/2003"], |
9d48860e |
517 | ); |
32eab2da |
518 | |
519 | The first value in the array is the actual SQL. Any other values are |
520 | optional and would be included in the bind values array. This gives |
521 | you: |
522 | |
523 | my($stmt, @bind) = $sql->insert('people', \%data); |
524 | |
9d48860e |
525 | $stmt = "INSERT INTO people (name, date_entered) |
32eab2da |
526 | VALUES (?, to_date(?,'MM/DD/YYYY'))"; |
527 | @bind = ('Bill', '03/02/2003'); |
528 | |
529 | An UPDATE is just as easy, all you change is the name of the function: |
530 | |
531 | my($stmt, @bind) = $sql->update('people', \%data); |
532 | |
533 | Notice that your C<%data> isn't touched; the module will generate |
534 | the appropriately quirky SQL for you automatically. Usually you'll |
535 | want to specify a WHERE clause for your UPDATE, though, which is |
536 | where handling C<%where> hashes comes in handy... |
537 | |
96449e8e |
538 | =head2 Complex where statements |
539 | |
32eab2da |
540 | This module can generate pretty complicated WHERE statements |
541 | easily. For example, simple C<key=value> pairs are taken to mean |
542 | equality, and if you want to see if a field is within a set |
543 | of values, you can use an arrayref. Let's say we wanted to |
544 | SELECT some data based on this criteria: |
545 | |
546 | my %where = ( |
547 | requestor => 'inna', |
548 | worker => ['nwiger', 'rcwe', 'sfz'], |
549 | status => { '!=', 'completed' } |
550 | ); |
551 | |
552 | my($stmt, @bind) = $sql->select('tickets', '*', \%where); |
553 | |
554 | The above would give you something like this: |
555 | |
556 | $stmt = "SELECT * FROM tickets WHERE |
557 | ( requestor = ? ) AND ( status != ? ) |
558 | AND ( worker = ? OR worker = ? OR worker = ? )"; |
559 | @bind = ('inna', 'completed', 'nwiger', 'rcwe', 'sfz'); |
560 | |
561 | Which you could then use in DBI code like so: |
562 | |
563 | my $sth = $dbh->prepare($stmt); |
564 | $sth->execute(@bind); |
565 | |
566 | Easy, eh? |
567 | |
568 | =head1 FUNCTIONS |
569 | |
570 | The functions are simple. There's one for each major SQL operation, |
571 | and a constructor you use first. The arguments are specified in a |
9d48860e |
572 | similar order to each function (table, then fields, then a where |
32eab2da |
573 | clause) to try and simplify things. |
574 | |
83cab70b |
575 | |
83cab70b |
576 | |
32eab2da |
577 | |
578 | =head2 new(option => 'value') |
579 | |
580 | The C<new()> function takes a list of options and values, and returns |
581 | a new B<SQL::Abstract> object which can then be used to generate SQL |
582 | through the methods below. The options accepted are: |
583 | |
584 | =over |
585 | |
586 | =item case |
587 | |
588 | If set to 'lower', then SQL will be generated in all lowercase. By |
589 | default SQL is generated in "textbook" case meaning something like: |
590 | |
591 | SELECT a_field FROM a_table WHERE some_field LIKE '%someval%' |
592 | |
96449e8e |
593 | Any setting other than 'lower' is ignored. |
594 | |
32eab2da |
595 | =item cmp |
596 | |
597 | This determines what the default comparison operator is. By default |
598 | it is C<=>, meaning that a hash like this: |
599 | |
600 | %where = (name => 'nwiger', email => 'nate@wiger.org'); |
601 | |
602 | Will generate SQL like this: |
603 | |
604 | WHERE name = 'nwiger' AND email = 'nate@wiger.org' |
605 | |
606 | However, you may want loose comparisons by default, so if you set |
607 | C<cmp> to C<like> you would get SQL such as: |
608 | |
609 | WHERE name like 'nwiger' AND email like 'nate@wiger.org' |
610 | |
611 | You can also override the comparsion on an individual basis - see |
612 | the huge section on L</"WHERE CLAUSES"> at the bottom. |
613 | |
96449e8e |
614 | =item sqltrue, sqlfalse |
615 | |
616 | Expressions for inserting boolean values within SQL statements. |
6e0c6552 |
617 | By default these are C<1=1> and C<1=0>. They are used |
618 | by the special operators C<-in> and C<-not_in> for generating |
619 | correct SQL even when the argument is an empty array (see below). |
96449e8e |
620 | |
32eab2da |
621 | =item logic |
622 | |
623 | This determines the default logical operator for multiple WHERE |
7cac25e6 |
624 | statements in arrays or hashes. If absent, the default logic is "or" |
625 | for arrays, and "and" for hashes. This means that a WHERE |
32eab2da |
626 | array of the form: |
627 | |
628 | @where = ( |
9d48860e |
629 | event_date => {'>=', '2/13/99'}, |
630 | event_date => {'<=', '4/24/03'}, |
32eab2da |
631 | ); |
632 | |
7cac25e6 |
633 | will generate SQL like this: |
32eab2da |
634 | |
635 | WHERE event_date >= '2/13/99' OR event_date <= '4/24/03' |
636 | |
637 | This is probably not what you want given this query, though (look |
638 | at the dates). To change the "OR" to an "AND", simply specify: |
639 | |
640 | my $sql = SQL::Abstract->new(logic => 'and'); |
641 | |
642 | Which will change the above C<WHERE> to: |
643 | |
644 | WHERE event_date >= '2/13/99' AND event_date <= '4/24/03' |
645 | |
96449e8e |
646 | The logic can also be changed locally by inserting |
7cac25e6 |
647 | a modifier in front of an arrayref : |
96449e8e |
648 | |
9d48860e |
649 | @where = (-and => [event_date => {'>=', '2/13/99'}, |
7cac25e6 |
650 | event_date => {'<=', '4/24/03'} ]); |
96449e8e |
651 | |
652 | See the L</"WHERE CLAUSES"> section for explanations. |
653 | |
32eab2da |
654 | =item convert |
655 | |
656 | This will automatically convert comparisons using the specified SQL |
657 | function for both column and value. This is mostly used with an argument |
658 | of C<upper> or C<lower>, so that the SQL will have the effect of |
659 | case-insensitive "searches". For example, this: |
660 | |
661 | $sql = SQL::Abstract->new(convert => 'upper'); |
662 | %where = (keywords => 'MaKe iT CAse inSeNSItive'); |
663 | |
664 | Will turn out the following SQL: |
665 | |
666 | WHERE upper(keywords) like upper('MaKe iT CAse inSeNSItive') |
667 | |
668 | The conversion can be C<upper()>, C<lower()>, or any other SQL function |
669 | that can be applied symmetrically to fields (actually B<SQL::Abstract> does |
670 | not validate this option; it will just pass through what you specify verbatim). |
671 | |
672 | =item bindtype |
673 | |
674 | This is a kludge because many databases suck. For example, you can't |
675 | just bind values using DBI's C<execute()> for Oracle C<CLOB> or C<BLOB> fields. |
676 | Instead, you have to use C<bind_param()>: |
677 | |
678 | $sth->bind_param(1, 'reg data'); |
679 | $sth->bind_param(2, $lots, {ora_type => ORA_CLOB}); |
680 | |
681 | The problem is, B<SQL::Abstract> will normally just return a C<@bind> array, |
682 | which loses track of which field each slot refers to. Fear not. |
683 | |
684 | If you specify C<bindtype> in new, you can determine how C<@bind> is returned. |
685 | Currently, you can specify either C<normal> (default) or C<columns>. If you |
686 | specify C<columns>, you will get an array that looks like this: |
687 | |
688 | my $sql = SQL::Abstract->new(bindtype => 'columns'); |
689 | my($stmt, @bind) = $sql->insert(...); |
690 | |
691 | @bind = ( |
692 | [ 'column1', 'value1' ], |
693 | [ 'column2', 'value2' ], |
694 | [ 'column3', 'value3' ], |
695 | ); |
696 | |
697 | You can then iterate through this manually, using DBI's C<bind_param()>. |
e3f9dff4 |
698 | |
32eab2da |
699 | $sth->prepare($stmt); |
700 | my $i = 1; |
701 | for (@bind) { |
702 | my($col, $data) = @$_; |
703 | if ($col eq 'details' || $col eq 'comments') { |
704 | $sth->bind_param($i, $data, {ora_type => ORA_CLOB}); |
705 | } elsif ($col eq 'image') { |
706 | $sth->bind_param($i, $data, {ora_type => ORA_BLOB}); |
707 | } else { |
708 | $sth->bind_param($i, $data); |
709 | } |
710 | $i++; |
711 | } |
712 | $sth->execute; # execute without @bind now |
713 | |
714 | Now, why would you still use B<SQL::Abstract> if you have to do this crap? |
715 | Basically, the advantage is still that you don't have to care which fields |
716 | are or are not included. You could wrap that above C<for> loop in a simple |
717 | sub called C<bind_fields()> or something and reuse it repeatedly. You still |
718 | get a layer of abstraction over manual SQL specification. |
719 | |
deb148a2 |
720 | Note that if you set L</bindtype> to C<columns>, the C<\[$sql, @bind]> |
721 | construct (see L</Literal SQL with placeholders and bind values (subqueries)>) |
722 | will expect the bind values in this format. |
723 | |
32eab2da |
724 | =item quote_char |
725 | |
726 | This is the character that a table or column name will be quoted |
9d48860e |
727 | with. By default this is an empty string, but you could set it to |
32eab2da |
728 | the character C<`>, to generate SQL like this: |
729 | |
730 | SELECT `a_field` FROM `a_table` WHERE `some_field` LIKE '%someval%' |
731 | |
96449e8e |
732 | Alternatively, you can supply an array ref of two items, the first being the left |
733 | hand quote character, and the second the right hand quote character. For |
734 | example, you could supply C<['[',']']> for SQL Server 2000 compliant quotes |
735 | that generates SQL like this: |
736 | |
737 | SELECT [a_field] FROM [a_table] WHERE [some_field] LIKE '%someval%' |
738 | |
9d48860e |
739 | Quoting is useful if you have tables or columns names that are reserved |
96449e8e |
740 | words in your database's SQL dialect. |
32eab2da |
741 | |
742 | =item name_sep |
743 | |
744 | This is the character that separates a table and column name. It is |
745 | necessary to specify this when the C<quote_char> option is selected, |
746 | so that tables and column names can be individually quoted like this: |
747 | |
748 | SELECT `table`.`one_field` FROM `table` WHERE `table`.`other_field` = 1 |
749 | |
b6251592 |
750 | =item injection_guard |
751 | |
752 | A regular expression C<qr/.../> that is applied to any C<-function> and unquoted |
753 | column name specified in a query structure. This is a safety mechanism to avoid |
754 | injection attacks when mishandling user input e.g.: |
755 | |
756 | my %condition_as_column_value_pairs = get_values_from_user(); |
757 | $sqla->select( ... , \%condition_as_column_value_pairs ); |
758 | |
759 | If the expression matches an exception is thrown. Note that literal SQL |
760 | supplied via C<\'...'> or C<\['...']> is B<not> checked in any way. |
761 | |
762 | Defaults to checking for C<;> and the C<GO> keyword (TransactSQL) |
763 | |
96449e8e |
764 | =item array_datatypes |
32eab2da |
765 | |
9d48860e |
766 | When this option is true, arrayrefs in INSERT or UPDATE are |
767 | interpreted as array datatypes and are passed directly |
96449e8e |
768 | to the DBI layer. |
769 | When this option is false, arrayrefs are interpreted |
770 | as literal SQL, just like refs to arrayrefs |
771 | (but this behavior is for backwards compatibility; when writing |
772 | new queries, use the "reference to arrayref" syntax |
773 | for literal SQL). |
32eab2da |
774 | |
32eab2da |
775 | |
96449e8e |
776 | =item special_ops |
32eab2da |
777 | |
9d48860e |
778 | Takes a reference to a list of "special operators" |
96449e8e |
779 | to extend the syntax understood by L<SQL::Abstract>. |
780 | See section L</"SPECIAL OPERATORS"> for details. |
32eab2da |
781 | |
59f23b3d |
782 | =item unary_ops |
783 | |
9d48860e |
784 | Takes a reference to a list of "unary operators" |
59f23b3d |
785 | to extend the syntax understood by L<SQL::Abstract>. |
786 | See section L</"UNARY OPERATORS"> for details. |
787 | |
32eab2da |
788 | |
32eab2da |
789 | |
96449e8e |
790 | =back |
32eab2da |
791 | |
02288357 |
792 | =head2 insert($table, \@values || \%fieldvals, \%options) |
32eab2da |
793 | |
794 | This is the simplest function. You simply give it a table name |
795 | and either an arrayref of values or hashref of field/value pairs. |
796 | It returns an SQL INSERT statement and a list of bind values. |
96449e8e |
797 | See the sections on L</"Inserting and Updating Arrays"> and |
798 | L</"Inserting and Updating SQL"> for information on how to insert |
799 | with those data types. |
32eab2da |
800 | |
02288357 |
801 | The optional C<\%options> hash reference may contain additional |
802 | options to generate the insert SQL. Currently supported options |
803 | are: |
804 | |
805 | =over 4 |
806 | |
807 | =item returning |
808 | |
809 | Takes either a scalar of raw SQL fields, or an array reference of |
810 | field names, and adds on an SQL C<RETURNING> statement at the end. |
811 | This allows you to return data generated by the insert statement |
812 | (such as row IDs) without performing another C<SELECT> statement. |
813 | Note, however, this is not part of the SQL standard and may not |
814 | be supported by all database engines. |
815 | |
816 | =back |
817 | |
32eab2da |
818 | =head2 update($table, \%fieldvals, \%where) |
819 | |
820 | This takes a table, hashref of field/value pairs, and an optional |
86298391 |
821 | hashref L<WHERE clause|/WHERE CLAUSES>. It returns an SQL UPDATE function and a list |
32eab2da |
822 | of bind values. |
96449e8e |
823 | See the sections on L</"Inserting and Updating Arrays"> and |
824 | L</"Inserting and Updating SQL"> for information on how to insert |
825 | with those data types. |
32eab2da |
826 | |
96449e8e |
827 | =head2 select($source, $fields, $where, $order) |
32eab2da |
828 | |
9d48860e |
829 | This returns a SQL SELECT statement and associated list of bind values, as |
96449e8e |
830 | specified by the arguments : |
32eab2da |
831 | |
96449e8e |
832 | =over |
32eab2da |
833 | |
96449e8e |
834 | =item $source |
32eab2da |
835 | |
9d48860e |
836 | Specification of the 'FROM' part of the statement. |
96449e8e |
837 | The argument can be either a plain scalar (interpreted as a table |
838 | name, will be quoted), or an arrayref (interpreted as a list |
839 | of table names, joined by commas, quoted), or a scalarref |
840 | (literal table name, not quoted), or a ref to an arrayref |
841 | (list of literal table names, joined by commas, not quoted). |
32eab2da |
842 | |
96449e8e |
843 | =item $fields |
32eab2da |
844 | |
9d48860e |
845 | Specification of the list of fields to retrieve from |
96449e8e |
846 | the source. |
847 | The argument can be either an arrayref (interpreted as a list |
9d48860e |
848 | of field names, will be joined by commas and quoted), or a |
96449e8e |
849 | plain scalar (literal SQL, not quoted). |
850 | Please observe that this API is not as flexible as for |
e3f9dff4 |
851 | the first argument C<$table>, for backwards compatibility reasons. |
32eab2da |
852 | |
96449e8e |
853 | =item $where |
32eab2da |
854 | |
96449e8e |
855 | Optional argument to specify the WHERE part of the query. |
856 | The argument is most often a hashref, but can also be |
9d48860e |
857 | an arrayref or plain scalar -- |
96449e8e |
858 | see section L<WHERE clause|/"WHERE CLAUSES"> for details. |
32eab2da |
859 | |
96449e8e |
860 | =item $order |
32eab2da |
861 | |
96449e8e |
862 | Optional argument to specify the ORDER BY part of the query. |
9d48860e |
863 | The argument can be a scalar, a hashref or an arrayref |
96449e8e |
864 | -- see section L<ORDER BY clause|/"ORDER BY CLAUSES"> |
865 | for details. |
32eab2da |
866 | |
96449e8e |
867 | =back |
32eab2da |
868 | |
32eab2da |
869 | |
870 | =head2 delete($table, \%where) |
871 | |
86298391 |
872 | This takes a table name and optional hashref L<WHERE clause|/WHERE CLAUSES>. |
32eab2da |
873 | It returns an SQL DELETE statement and list of bind values. |
874 | |
32eab2da |
875 | =head2 where(\%where, \@order) |
876 | |
877 | This is used to generate just the WHERE clause. For example, |
878 | if you have an arbitrary data structure and know what the |
879 | rest of your SQL is going to look like, but want an easy way |
880 | to produce a WHERE clause, use this. It returns an SQL WHERE |
881 | clause and list of bind values. |
882 | |
32eab2da |
883 | |
884 | =head2 values(\%data) |
885 | |
886 | This just returns the values from the hash C<%data>, in the same |
887 | order that would be returned from any of the other above queries. |
888 | Using this allows you to markedly speed up your queries if you |
889 | are affecting lots of rows. See below under the L</"PERFORMANCE"> section. |
890 | |
32eab2da |
891 | =head2 generate($any, 'number', $of, \@data, $struct, \%types) |
892 | |
893 | Warning: This is an experimental method and subject to change. |
894 | |
895 | This returns arbitrarily generated SQL. It's a really basic shortcut. |
896 | It will return two different things, depending on return context: |
897 | |
898 | my($stmt, @bind) = $sql->generate('create table', \$table, \@fields); |
899 | my $stmt_and_val = $sql->generate('create table', \$table, \@fields); |
900 | |
901 | These would return the following: |
902 | |
903 | # First calling form |
904 | $stmt = "CREATE TABLE test (?, ?)"; |
905 | @bind = (field1, field2); |
906 | |
907 | # Second calling form |
908 | $stmt_and_val = "CREATE TABLE test (field1, field2)"; |
909 | |
910 | Depending on what you're trying to do, it's up to you to choose the correct |
911 | format. In this example, the second form is what you would want. |
912 | |
913 | By the same token: |
914 | |
915 | $sql->generate('alter session', { nls_date_format => 'MM/YY' }); |
916 | |
917 | Might give you: |
918 | |
919 | ALTER SESSION SET nls_date_format = 'MM/YY' |
920 | |
921 | You get the idea. Strings get their case twiddled, but everything |
922 | else remains verbatim. |
923 | |
32eab2da |
924 | =head1 WHERE CLAUSES |
925 | |
96449e8e |
926 | =head2 Introduction |
927 | |
32eab2da |
928 | This module uses a variation on the idea from L<DBIx::Abstract>. It |
929 | is B<NOT>, repeat I<not> 100% compatible. B<The main logic of this |
930 | module is that things in arrays are OR'ed, and things in hashes |
931 | are AND'ed.> |
932 | |
933 | The easiest way to explain is to show lots of examples. After |
934 | each C<%where> hash shown, it is assumed you used: |
935 | |
936 | my($stmt, @bind) = $sql->where(\%where); |
937 | |
938 | However, note that the C<%where> hash can be used directly in any |
939 | of the other functions as well, as described above. |
940 | |
96449e8e |
941 | =head2 Key-value pairs |
942 | |
32eab2da |
943 | So, let's get started. To begin, a simple hash: |
944 | |
945 | my %where = ( |
946 | user => 'nwiger', |
947 | status => 'completed' |
948 | ); |
949 | |
950 | Is converted to SQL C<key = val> statements: |
951 | |
952 | $stmt = "WHERE user = ? AND status = ?"; |
953 | @bind = ('nwiger', 'completed'); |
954 | |
955 | One common thing I end up doing is having a list of values that |
956 | a field can be in. To do this, simply specify a list inside of |
957 | an arrayref: |
958 | |
959 | my %where = ( |
960 | user => 'nwiger', |
961 | status => ['assigned', 'in-progress', 'pending']; |
962 | ); |
963 | |
964 | This simple code will create the following: |
9d48860e |
965 | |
32eab2da |
966 | $stmt = "WHERE user = ? AND ( status = ? OR status = ? OR status = ? )"; |
967 | @bind = ('nwiger', 'assigned', 'in-progress', 'pending'); |
968 | |
9d48860e |
969 | A field associated to an empty arrayref will be considered a |
7cac25e6 |
970 | logical false and will generate 0=1. |
8a68b5be |
971 | |
b864ba9b |
972 | =head2 Tests for NULL values |
973 | |
974 | If the value part is C<undef> then this is converted to SQL <IS NULL> |
975 | |
976 | my %where = ( |
977 | user => 'nwiger', |
978 | status => undef, |
979 | ); |
980 | |
981 | becomes: |
982 | |
983 | $stmt = "WHERE user = ? AND status IS NULL"; |
984 | @bind = ('nwiger'); |
985 | |
e9614080 |
986 | To test if a column IS NOT NULL: |
987 | |
988 | my %where = ( |
989 | user => 'nwiger', |
990 | status => { '!=', undef }, |
991 | ); |
cc422895 |
992 | |
6e0c6552 |
993 | =head2 Specific comparison operators |
96449e8e |
994 | |
32eab2da |
995 | If you want to specify a different type of operator for your comparison, |
996 | you can use a hashref for a given column: |
997 | |
998 | my %where = ( |
999 | user => 'nwiger', |
1000 | status => { '!=', 'completed' } |
1001 | ); |
1002 | |
1003 | Which would generate: |
1004 | |
1005 | $stmt = "WHERE user = ? AND status != ?"; |
1006 | @bind = ('nwiger', 'completed'); |
1007 | |
1008 | To test against multiple values, just enclose the values in an arrayref: |
1009 | |
96449e8e |
1010 | status => { '=', ['assigned', 'in-progress', 'pending'] }; |
1011 | |
f2d5020d |
1012 | Which would give you: |
96449e8e |
1013 | |
1014 | "WHERE status = ? OR status = ? OR status = ?" |
1015 | |
1016 | |
1017 | The hashref can also contain multiple pairs, in which case it is expanded |
32eab2da |
1018 | into an C<AND> of its elements: |
1019 | |
1020 | my %where = ( |
1021 | user => 'nwiger', |
1022 | status => { '!=', 'completed', -not_like => 'pending%' } |
1023 | ); |
1024 | |
1025 | # Or more dynamically, like from a form |
1026 | $where{user} = 'nwiger'; |
1027 | $where{status}{'!='} = 'completed'; |
1028 | $where{status}{'-not_like'} = 'pending%'; |
1029 | |
1030 | # Both generate this |
1031 | $stmt = "WHERE user = ? AND status != ? AND status NOT LIKE ?"; |
1032 | @bind = ('nwiger', 'completed', 'pending%'); |
1033 | |
96449e8e |
1034 | |
32eab2da |
1035 | To get an OR instead, you can combine it with the arrayref idea: |
1036 | |
1037 | my %where => ( |
1038 | user => 'nwiger', |
1a6f2a03 |
1039 | priority => [ { '=', 2 }, { '>', 5 } ] |
32eab2da |
1040 | ); |
1041 | |
1042 | Which would generate: |
1043 | |
1a6f2a03 |
1044 | $stmt = "WHERE ( priority = ? OR priority > ? ) AND user = ?"; |
1045 | @bind = ('2', '5', 'nwiger'); |
32eab2da |
1046 | |
44b9e502 |
1047 | If you want to include literal SQL (with or without bind values), just use a |
1048 | scalar reference or array reference as the value: |
1049 | |
1050 | my %where = ( |
1051 | date_entered => { '>' => \["to_date(?, 'MM/DD/YYYY')", "11/26/2008"] }, |
1052 | date_expires => { '<' => \"now()" } |
1053 | ); |
1054 | |
1055 | Which would generate: |
1056 | |
1057 | $stmt = "WHERE date_entered > "to_date(?, 'MM/DD/YYYY') AND date_expires < now()"; |
1058 | @bind = ('11/26/2008'); |
1059 | |
96449e8e |
1060 | |
1061 | =head2 Logic and nesting operators |
1062 | |
1063 | In the example above, |
1064 | there is a subtle trap if you want to say something like |
32eab2da |
1065 | this (notice the C<AND>): |
1066 | |
1067 | WHERE priority != ? AND priority != ? |
1068 | |
1069 | Because, in Perl you I<can't> do this: |
1070 | |
1071 | priority => { '!=', 2, '!=', 1 } |
1072 | |
1073 | As the second C<!=> key will obliterate the first. The solution |
1074 | is to use the special C<-modifier> form inside an arrayref: |
1075 | |
9d48860e |
1076 | priority => [ -and => {'!=', 2}, |
96449e8e |
1077 | {'!=', 1} ] |
1078 | |
32eab2da |
1079 | |
1080 | Normally, these would be joined by C<OR>, but the modifier tells it |
1081 | to use C<AND> instead. (Hint: You can use this in conjunction with the |
1082 | C<logic> option to C<new()> in order to change the way your queries |
1083 | work by default.) B<Important:> Note that the C<-modifier> goes |
1084 | B<INSIDE> the arrayref, as an extra first element. This will |
1085 | B<NOT> do what you think it might: |
1086 | |
1087 | priority => -and => [{'!=', 2}, {'!=', 1}] # WRONG! |
1088 | |
1089 | Here is a quick list of equivalencies, since there is some overlap: |
1090 | |
1091 | # Same |
1092 | status => {'!=', 'completed', 'not like', 'pending%' } |
1093 | status => [ -and => {'!=', 'completed'}, {'not like', 'pending%'}] |
1094 | |
1095 | # Same |
1096 | status => {'=', ['assigned', 'in-progress']} |
1097 | status => [ -or => {'=', 'assigned'}, {'=', 'in-progress'}] |
1098 | status => [ {'=', 'assigned'}, {'=', 'in-progress'} ] |
1099 | |
e3f9dff4 |
1100 | |
1101 | |
96449e8e |
1102 | =head2 Special operators : IN, BETWEEN, etc. |
1103 | |
32eab2da |
1104 | You can also use the hashref format to compare a list of fields using the |
1105 | C<IN> comparison operator, by specifying the list as an arrayref: |
1106 | |
1107 | my %where = ( |
1108 | status => 'completed', |
1109 | reportid => { -in => [567, 2335, 2] } |
1110 | ); |
1111 | |
1112 | Which would generate: |
1113 | |
1114 | $stmt = "WHERE status = ? AND reportid IN (?,?,?)"; |
1115 | @bind = ('completed', '567', '2335', '2'); |
1116 | |
9d48860e |
1117 | The reverse operator C<-not_in> generates SQL C<NOT IN> and is used in |
96449e8e |
1118 | the same way. |
1119 | |
6e0c6552 |
1120 | If the argument to C<-in> is an empty array, 'sqlfalse' is generated |
1121 | (by default : C<1=0>). Similarly, C<< -not_in => [] >> generates |
1122 | 'sqltrue' (by default : C<1=1>). |
1123 | |
e41c3bdd |
1124 | In addition to the array you can supply a chunk of literal sql or |
1125 | literal sql with bind: |
6e0c6552 |
1126 | |
e41c3bdd |
1127 | my %where = { |
1128 | customer => { -in => \[ |
1129 | 'SELECT cust_id FROM cust WHERE balance > ?', |
1130 | 2000, |
1131 | ], |
1132 | status => { -in => \'SELECT status_codes FROM states' }, |
1133 | }; |
6e0c6552 |
1134 | |
e41c3bdd |
1135 | would generate: |
1136 | |
1137 | $stmt = "WHERE ( |
1138 | customer IN ( SELECT cust_id FROM cust WHERE balance > ? ) |
1139 | AND status IN ( SELECT status_codes FROM states ) |
1140 | )"; |
1141 | @bind = ('2000'); |
1142 | |
1143 | |
1144 | |
1145 | Another pair of operators is C<-between> and C<-not_between>, |
96449e8e |
1146 | used with an arrayref of two values: |
32eab2da |
1147 | |
1148 | my %where = ( |
1149 | user => 'nwiger', |
1150 | completion_date => { |
1151 | -not_between => ['2002-10-01', '2003-02-06'] |
1152 | } |
1153 | ); |
1154 | |
1155 | Would give you: |
1156 | |
1157 | WHERE user = ? AND completion_date NOT BETWEEN ( ? AND ? ) |
1158 | |
e41c3bdd |
1159 | Just like with C<-in> all plausible combinations of literal SQL |
1160 | are possible: |
1161 | |
1162 | my %where = { |
1163 | start0 => { -between => [ 1, 2 ] }, |
1164 | start1 => { -between => \["? AND ?", 1, 2] }, |
1165 | start2 => { -between => \"lower(x) AND upper(y)" }, |
9d48860e |
1166 | start3 => { -between => [ |
e41c3bdd |
1167 | \"lower(x)", |
1168 | \["upper(?)", 'stuff' ], |
1169 | ] }, |
1170 | }; |
1171 | |
1172 | Would give you: |
1173 | |
1174 | $stmt = "WHERE ( |
1175 | ( start0 BETWEEN ? AND ? ) |
1176 | AND ( start1 BETWEEN ? AND ? ) |
1177 | AND ( start2 BETWEEN lower(x) AND upper(y) ) |
1178 | AND ( start3 BETWEEN lower(x) AND upper(?) ) |
1179 | )"; |
1180 | @bind = (1, 2, 1, 2, 'stuff'); |
1181 | |
1182 | |
9d48860e |
1183 | These are the two builtin "special operators"; but the |
96449e8e |
1184 | list can be expanded : see section L</"SPECIAL OPERATORS"> below. |
1185 | |
59f23b3d |
1186 | =head2 Unary operators: bool |
97a920ef |
1187 | |
1188 | If you wish to test against boolean columns or functions within your |
1189 | database you can use the C<-bool> and C<-not_bool> operators. For |
1190 | example to test the column C<is_user> being true and the column |
827bb0eb |
1191 | C<is_enabled> being false you would use:- |
97a920ef |
1192 | |
1193 | my %where = ( |
1194 | -bool => 'is_user', |
1195 | -not_bool => 'is_enabled', |
1196 | ); |
1197 | |
1198 | Would give you: |
1199 | |
277b5d3f |
1200 | WHERE is_user AND NOT is_enabled |
97a920ef |
1201 | |
0b604e9d |
1202 | If a more complex combination is required, testing more conditions, |
1203 | then you should use the and/or operators:- |
1204 | |
1205 | my %where = ( |
1206 | -and => [ |
1207 | -bool => 'one', |
1208 | -bool => 'two', |
1209 | -bool => 'three', |
1210 | -not_bool => 'four', |
1211 | ], |
1212 | ); |
1213 | |
1214 | Would give you: |
1215 | |
1216 | WHERE one AND two AND three AND NOT four |
97a920ef |
1217 | |
1218 | |
107b72f1 |
1219 | =head2 Nested conditions, -and/-or prefixes |
96449e8e |
1220 | |
32eab2da |
1221 | So far, we've seen how multiple conditions are joined with a top-level |
1222 | C<AND>. We can change this by putting the different conditions we want in |
1223 | hashes and then putting those hashes in an array. For example: |
1224 | |
1225 | my @where = ( |
1226 | { |
1227 | user => 'nwiger', |
1228 | status => { -like => ['pending%', 'dispatched'] }, |
1229 | }, |
1230 | { |
1231 | user => 'robot', |
1232 | status => 'unassigned', |
1233 | } |
1234 | ); |
1235 | |
1236 | This data structure would create the following: |
1237 | |
1238 | $stmt = "WHERE ( user = ? AND ( status LIKE ? OR status LIKE ? ) ) |
1239 | OR ( user = ? AND status = ? ) )"; |
1240 | @bind = ('nwiger', 'pending', 'dispatched', 'robot', 'unassigned'); |
1241 | |
107b72f1 |
1242 | |
48d9f5f8 |
1243 | Clauses in hashrefs or arrayrefs can be prefixed with an C<-and> or C<-or> |
1244 | to change the logic inside : |
32eab2da |
1245 | |
1246 | my @where = ( |
1247 | -and => [ |
1248 | user => 'nwiger', |
48d9f5f8 |
1249 | [ |
1250 | -and => [ workhrs => {'>', 20}, geo => 'ASIA' ], |
1251 | -or => { workhrs => {'<', 50}, geo => 'EURO' }, |
32eab2da |
1252 | ], |
1253 | ], |
1254 | ); |
1255 | |
1256 | That would yield: |
1257 | |
48d9f5f8 |
1258 | WHERE ( user = ? AND ( |
1259 | ( workhrs > ? AND geo = ? ) |
1260 | OR ( workhrs < ? OR geo = ? ) |
1261 | ) ) |
107b72f1 |
1262 | |
cc422895 |
1263 | =head3 Algebraic inconsistency, for historical reasons |
107b72f1 |
1264 | |
7cac25e6 |
1265 | C<Important note>: when connecting several conditions, the C<-and->|C<-or> |
1266 | operator goes C<outside> of the nested structure; whereas when connecting |
1267 | several constraints on one column, the C<-and> operator goes |
1268 | C<inside> the arrayref. Here is an example combining both features : |
1269 | |
1270 | my @where = ( |
1271 | -and => [a => 1, b => 2], |
1272 | -or => [c => 3, d => 4], |
1273 | e => [-and => {-like => 'foo%'}, {-like => '%bar'} ] |
1274 | ) |
1275 | |
1276 | yielding |
1277 | |
9d48860e |
1278 | WHERE ( ( ( a = ? AND b = ? ) |
1279 | OR ( c = ? OR d = ? ) |
7cac25e6 |
1280 | OR ( e LIKE ? AND e LIKE ? ) ) ) |
1281 | |
107b72f1 |
1282 | This difference in syntax is unfortunate but must be preserved for |
1283 | historical reasons. So be careful : the two examples below would |
1284 | seem algebraically equivalent, but they are not |
1285 | |
9d48860e |
1286 | {col => [-and => {-like => 'foo%'}, {-like => '%bar'}]} |
107b72f1 |
1287 | # yields : WHERE ( ( col LIKE ? AND col LIKE ? ) ) |
1288 | |
9d48860e |
1289 | [-and => {col => {-like => 'foo%'}, {col => {-like => '%bar'}}]] |
107b72f1 |
1290 | # yields : WHERE ( ( col LIKE ? OR col LIKE ? ) ) |
1291 | |
7cac25e6 |
1292 | |
cc422895 |
1293 | =head2 Literal SQL and value type operators |
96449e8e |
1294 | |
cc422895 |
1295 | The basic premise of SQL::Abstract is that in WHERE specifications the "left |
1296 | side" is a column name and the "right side" is a value (normally rendered as |
1297 | a placeholder). This holds true for both hashrefs and arrayref pairs as you |
1298 | see in the L</WHERE CLAUSES> examples above. Sometimes it is necessary to |
1299 | alter this behavior. There are several ways of doing so. |
e9614080 |
1300 | |
cc422895 |
1301 | =head3 -ident |
1302 | |
1303 | This is a virtual operator that signals the string to its right side is an |
1304 | identifier (a column name) and not a value. For example to compare two |
1305 | columns you would write: |
32eab2da |
1306 | |
e9614080 |
1307 | my %where = ( |
1308 | priority => { '<', 2 }, |
cc422895 |
1309 | requestor => { -ident => 'submitter' }, |
e9614080 |
1310 | ); |
1311 | |
1312 | which creates: |
1313 | |
1314 | $stmt = "WHERE priority < ? AND requestor = submitter"; |
1315 | @bind = ('2'); |
1316 | |
cc422895 |
1317 | If you are maintaining legacy code you may see a different construct as |
1318 | described in L</Deprecated usage of Literal SQL>, please use C<-ident> in new |
1319 | code. |
1320 | |
1321 | =head3 -value |
e9614080 |
1322 | |
cc422895 |
1323 | This is a virtual operator that signals that the construct to its right side |
1324 | is a value to be passed to DBI. This is for example necessary when you want |
1325 | to write a where clause against an array (for RDBMS that support such |
1326 | datatypes). For example: |
e9614080 |
1327 | |
32eab2da |
1328 | my %where = ( |
cc422895 |
1329 | array => { -value => [1, 2, 3] } |
32eab2da |
1330 | ); |
1331 | |
cc422895 |
1332 | will result in: |
32eab2da |
1333 | |
cc422895 |
1334 | $stmt = 'WHERE array = ?'; |
1335 | @bind = ([1, 2, 3]); |
32eab2da |
1336 | |
cc422895 |
1337 | Note that if you were to simply say: |
32eab2da |
1338 | |
1339 | my %where = ( |
cc422895 |
1340 | array => [1, 2, 3] |
32eab2da |
1341 | ); |
1342 | |
cc422895 |
1343 | the result would porbably be not what you wanted: |
1344 | |
1345 | $stmt = 'WHERE array = ? OR array = ? OR array = ?'; |
1346 | @bind = (1, 2, 3); |
1347 | |
1348 | =head3 Literal SQL |
96449e8e |
1349 | |
cc422895 |
1350 | Finally, sometimes only literal SQL will do. To include a random snippet |
1351 | of SQL verbatim, you specify it as a scalar reference. Consider this only |
1352 | as a last resort. Usually there is a better way. For example: |
96449e8e |
1353 | |
1354 | my %where = ( |
cc422895 |
1355 | priority => { '<', 2 }, |
1356 | requestor => { -in => \'(SELECT name FROM hitmen)' }, |
96449e8e |
1357 | ); |
1358 | |
cc422895 |
1359 | Would create: |
96449e8e |
1360 | |
cc422895 |
1361 | $stmt = "WHERE priority < ? AND requestor IN (SELECT name FROM hitmen)" |
1362 | @bind = (2); |
1363 | |
1364 | Note that in this example, you only get one bind parameter back, since |
1365 | the verbatim SQL is passed as part of the statement. |
1366 | |
1367 | =head4 CAVEAT |
1368 | |
1369 | Never use untrusted input as a literal SQL argument - this is a massive |
1370 | security risk (there is no way to check literal snippets for SQL |
1371 | injections and other nastyness). If you need to deal with untrusted input |
1372 | use literal SQL with placeholders as described next. |
96449e8e |
1373 | |
cc422895 |
1374 | =head3 Literal SQL with placeholders and bind values (subqueries) |
96449e8e |
1375 | |
1376 | If the literal SQL to be inserted has placeholders and bind values, |
1377 | use a reference to an arrayref (yes this is a double reference -- |
1378 | not so common, but perfectly legal Perl). For example, to find a date |
1379 | in Postgres you can use something like this: |
1380 | |
1381 | my %where = ( |
1382 | date_column => \[q/= date '2008-09-30' - ?::integer/, 10/] |
1383 | ) |
1384 | |
1385 | This would create: |
1386 | |
d2a8fe1a |
1387 | $stmt = "WHERE ( date_column = date '2008-09-30' - ?::integer )" |
96449e8e |
1388 | @bind = ('10'); |
1389 | |
deb148a2 |
1390 | Note that you must pass the bind values in the same format as they are returned |
62552e7d |
1391 | by L</where>. That means that if you set L</bindtype> to C<columns>, you must |
26f2dca5 |
1392 | provide the bind values in the C<< [ column_meta => value ] >> format, where |
1393 | C<column_meta> is an opaque scalar value; most commonly the column name, but |
62552e7d |
1394 | you can use any scalar value (including references and blessed references), |
1395 | L<SQL::Abstract> will simply pass it through intact. So if C<bindtype> is set |
1396 | to C<columns> the above example will look like: |
deb148a2 |
1397 | |
1398 | my %where = ( |
1399 | date_column => \[q/= date '2008-09-30' - ?::integer/, [ dummy => 10 ]/] |
1400 | ) |
96449e8e |
1401 | |
1402 | Literal SQL is especially useful for nesting parenthesized clauses in the |
1403 | main SQL query. Here is a first example : |
1404 | |
1405 | my ($sub_stmt, @sub_bind) = ("SELECT c1 FROM t1 WHERE c2 < ? AND c3 LIKE ?", |
1406 | 100, "foo%"); |
1407 | my %where = ( |
1408 | foo => 1234, |
1409 | bar => \["IN ($sub_stmt)" => @sub_bind], |
1410 | ); |
1411 | |
1412 | This yields : |
1413 | |
9d48860e |
1414 | $stmt = "WHERE (foo = ? AND bar IN (SELECT c1 FROM t1 |
96449e8e |
1415 | WHERE c2 < ? AND c3 LIKE ?))"; |
1416 | @bind = (1234, 100, "foo%"); |
1417 | |
9d48860e |
1418 | Other subquery operators, like for example C<"E<gt> ALL"> or C<"NOT IN">, |
96449e8e |
1419 | are expressed in the same way. Of course the C<$sub_stmt> and |
9d48860e |
1420 | its associated bind values can be generated through a former call |
96449e8e |
1421 | to C<select()> : |
1422 | |
1423 | my ($sub_stmt, @sub_bind) |
9d48860e |
1424 | = $sql->select("t1", "c1", {c2 => {"<" => 100}, |
96449e8e |
1425 | c3 => {-like => "foo%"}}); |
1426 | my %where = ( |
1427 | foo => 1234, |
1428 | bar => \["> ALL ($sub_stmt)" => @sub_bind], |
1429 | ); |
1430 | |
1431 | In the examples above, the subquery was used as an operator on a column; |
9d48860e |
1432 | but the same principle also applies for a clause within the main C<%where> |
96449e8e |
1433 | hash, like an EXISTS subquery : |
1434 | |
9d48860e |
1435 | my ($sub_stmt, @sub_bind) |
96449e8e |
1436 | = $sql->select("t1", "*", {c1 => 1, c2 => \"> t0.c0"}); |
48d9f5f8 |
1437 | my %where = ( -and => [ |
96449e8e |
1438 | foo => 1234, |
48d9f5f8 |
1439 | \["EXISTS ($sub_stmt)" => @sub_bind], |
1440 | ]); |
96449e8e |
1441 | |
1442 | which yields |
1443 | |
9d48860e |
1444 | $stmt = "WHERE (foo = ? AND EXISTS (SELECT * FROM t1 |
96449e8e |
1445 | WHERE c1 = ? AND c2 > t0.c0))"; |
1446 | @bind = (1234, 1); |
1447 | |
1448 | |
9d48860e |
1449 | Observe that the condition on C<c2> in the subquery refers to |
1450 | column C<t0.c0> of the main query : this is I<not> a bind |
1451 | value, so we have to express it through a scalar ref. |
96449e8e |
1452 | Writing C<< c2 => {">" => "t0.c0"} >> would have generated |
1453 | C<< c2 > ? >> with bind value C<"t0.c0"> ... not exactly |
1454 | what we wanted here. |
1455 | |
96449e8e |
1456 | Finally, here is an example where a subquery is used |
1457 | for expressing unary negation: |
1458 | |
9d48860e |
1459 | my ($sub_stmt, @sub_bind) |
96449e8e |
1460 | = $sql->where({age => [{"<" => 10}, {">" => 20}]}); |
1461 | $sub_stmt =~ s/^ where //i; # don't want "WHERE" in the subclause |
1462 | my %where = ( |
1463 | lname => {like => '%son%'}, |
48d9f5f8 |
1464 | \["NOT ($sub_stmt)" => @sub_bind], |
96449e8e |
1465 | ); |
1466 | |
1467 | This yields |
1468 | |
1469 | $stmt = "lname LIKE ? AND NOT ( age < ? OR age > ? )" |
1470 | @bind = ('%son%', 10, 20) |
1471 | |
cc422895 |
1472 | =head3 Deprecated usage of Literal SQL |
1473 | |
1474 | Below are some examples of archaic use of literal SQL. It is shown only as |
1475 | reference for those who deal with legacy code. Each example has a much |
1476 | better, cleaner and safer alternative that users should opt for in new code. |
1477 | |
1478 | =over |
1479 | |
1480 | =item * |
1481 | |
1482 | my %where = ( requestor => \'IS NOT NULL' ) |
1483 | |
1484 | $stmt = "WHERE requestor IS NOT NULL" |
1485 | |
1486 | This used to be the way of generating NULL comparisons, before the handling |
1487 | of C<undef> got formalized. For new code please use the superior syntax as |
1488 | described in L</Tests for NULL values>. |
96449e8e |
1489 | |
cc422895 |
1490 | =item * |
1491 | |
1492 | my %where = ( requestor => \'= submitter' ) |
1493 | |
1494 | $stmt = "WHERE requestor = submitter" |
1495 | |
1496 | This used to be the only way to compare columns. Use the superior L</-ident> |
1497 | method for all new code. For example an identifier declared in such a way |
1498 | will be properly quoted if L</quote_char> is properly set, while the legacy |
1499 | form will remain as supplied. |
1500 | |
1501 | =item * |
1502 | |
1503 | my %where = ( is_ready => \"", completed => { '>', '2012-12-21' } ) |
1504 | |
1505 | $stmt = "WHERE completed > ? AND is_ready" |
1506 | @bind = ('2012-12-21') |
1507 | |
1508 | Using an empty string literal used to be the only way to express a boolean. |
1509 | For all new code please use the much more readable |
1510 | L<-bool|/Unary operators: bool> operator. |
1511 | |
1512 | =back |
96449e8e |
1513 | |
1514 | =head2 Conclusion |
1515 | |
32eab2da |
1516 | These pages could go on for a while, since the nesting of the data |
1517 | structures this module can handle are pretty much unlimited (the |
1518 | module implements the C<WHERE> expansion as a recursive function |
1519 | internally). Your best bet is to "play around" with the module a |
1520 | little to see how the data structures behave, and choose the best |
1521 | format for your data based on that. |
1522 | |
1523 | And of course, all the values above will probably be replaced with |
1524 | variables gotten from forms or the command line. After all, if you |
1525 | knew everything ahead of time, you wouldn't have to worry about |
1526 | dynamically-generating SQL and could just hardwire it into your |
1527 | script. |
1528 | |
86298391 |
1529 | =head1 ORDER BY CLAUSES |
1530 | |
9d48860e |
1531 | Some functions take an order by clause. This can either be a scalar (just a |
86298391 |
1532 | column name,) a hash of C<< { -desc => 'col' } >> or C<< { -asc => 'col' } >>, |
1cfa1db3 |
1533 | or an array of either of the two previous forms. Examples: |
1534 | |
952f9e2d |
1535 | Given | Will Generate |
1cfa1db3 |
1536 | ---------------------------------------------------------- |
952f9e2d |
1537 | | |
1538 | \'colA DESC' | ORDER BY colA DESC |
1539 | | |
1540 | 'colA' | ORDER BY colA |
1541 | | |
1542 | [qw/colA colB/] | ORDER BY colA, colB |
1543 | | |
1544 | {-asc => 'colA'} | ORDER BY colA ASC |
1545 | | |
1546 | {-desc => 'colB'} | ORDER BY colB DESC |
1547 | | |
1548 | ['colA', {-asc => 'colB'}] | ORDER BY colA, colB ASC |
1549 | | |
855e6047 |
1550 | { -asc => [qw/colA colB/] } | ORDER BY colA ASC, colB ASC |
952f9e2d |
1551 | | |
1552 | [ | |
1553 | { -asc => 'colA' }, | ORDER BY colA ASC, colB DESC, |
1554 | { -desc => [qw/colB/], | colC ASC, colD ASC |
1555 | { -asc => [qw/colC colD/],| |
1556 | ] | |
1557 | =========================================================== |
86298391 |
1558 | |
96449e8e |
1559 | |
1560 | |
1561 | =head1 SPECIAL OPERATORS |
1562 | |
e3f9dff4 |
1563 | my $sqlmaker = SQL::Abstract->new(special_ops => [ |
3a2e1a5e |
1564 | { |
1565 | regex => qr/.../, |
e3f9dff4 |
1566 | handler => sub { |
1567 | my ($self, $field, $op, $arg) = @_; |
1568 | ... |
3a2e1a5e |
1569 | }, |
1570 | }, |
1571 | { |
1572 | regex => qr/.../, |
1573 | handler => 'method_name', |
e3f9dff4 |
1574 | }, |
1575 | ]); |
1576 | |
9d48860e |
1577 | A "special operator" is a SQL syntactic clause that can be |
e3f9dff4 |
1578 | applied to a field, instead of a usual binary operator. |
9d48860e |
1579 | For example : |
e3f9dff4 |
1580 | |
1581 | WHERE field IN (?, ?, ?) |
1582 | WHERE field BETWEEN ? AND ? |
1583 | WHERE MATCH(field) AGAINST (?, ?) |
96449e8e |
1584 | |
e3f9dff4 |
1585 | Special operators IN and BETWEEN are fairly standard and therefore |
3a2e1a5e |
1586 | are builtin within C<SQL::Abstract> (as the overridable methods |
1587 | C<_where_field_IN> and C<_where_field_BETWEEN>). For other operators, |
1588 | like the MATCH .. AGAINST example above which is specific to MySQL, |
1589 | you can write your own operator handlers - supply a C<special_ops> |
1590 | argument to the C<new> method. That argument takes an arrayref of |
1591 | operator definitions; each operator definition is a hashref with two |
1592 | entries: |
96449e8e |
1593 | |
e3f9dff4 |
1594 | =over |
1595 | |
1596 | =item regex |
1597 | |
1598 | the regular expression to match the operator |
96449e8e |
1599 | |
e3f9dff4 |
1600 | =item handler |
1601 | |
3a2e1a5e |
1602 | Either a coderef or a plain scalar method name. In both cases |
1603 | the expected return is C<< ($sql, @bind) >>. |
1604 | |
1605 | When supplied with a method name, it is simply called on the |
1606 | L<SQL::Abstract/> object as: |
1607 | |
1608 | $self->$method_name ($field, $op, $arg) |
1609 | |
1610 | Where: |
1611 | |
1612 | $op is the part that matched the handler regex |
1613 | $field is the LHS of the operator |
1614 | $arg is the RHS |
1615 | |
1616 | When supplied with a coderef, it is called as: |
1617 | |
1618 | $coderef->($self, $field, $op, $arg) |
1619 | |
e3f9dff4 |
1620 | |
1621 | =back |
1622 | |
9d48860e |
1623 | For example, here is an implementation |
e3f9dff4 |
1624 | of the MATCH .. AGAINST syntax for MySQL |
1625 | |
1626 | my $sqlmaker = SQL::Abstract->new(special_ops => [ |
9d48860e |
1627 | |
e3f9dff4 |
1628 | # special op for MySql MATCH (field) AGAINST(word1, word2, ...) |
9d48860e |
1629 | {regex => qr/^match$/i, |
e3f9dff4 |
1630 | handler => sub { |
1631 | my ($self, $field, $op, $arg) = @_; |
1632 | $arg = [$arg] if not ref $arg; |
1633 | my $label = $self->_quote($field); |
1634 | my ($placeholder) = $self->_convert('?'); |
1635 | my $placeholders = join ", ", (($placeholder) x @$arg); |
1636 | my $sql = $self->_sqlcase('match') . " ($label) " |
1637 | . $self->_sqlcase('against') . " ($placeholders) "; |
1638 | my @bind = $self->_bindtype($field, @$arg); |
1639 | return ($sql, @bind); |
1640 | } |
1641 | }, |
9d48860e |
1642 | |
e3f9dff4 |
1643 | ]); |
96449e8e |
1644 | |
1645 | |
59f23b3d |
1646 | =head1 UNARY OPERATORS |
1647 | |
112b5232 |
1648 | my $sqlmaker = SQL::Abstract->new(unary_ops => [ |
59f23b3d |
1649 | { |
1650 | regex => qr/.../, |
1651 | handler => sub { |
1652 | my ($self, $op, $arg) = @_; |
1653 | ... |
1654 | }, |
1655 | }, |
1656 | { |
1657 | regex => qr/.../, |
1658 | handler => 'method_name', |
1659 | }, |
1660 | ]); |
1661 | |
9d48860e |
1662 | A "unary operator" is a SQL syntactic clause that can be |
59f23b3d |
1663 | applied to a field - the operator goes before the field |
1664 | |
1665 | You can write your own operator handlers - supply a C<unary_ops> |
1666 | argument to the C<new> method. That argument takes an arrayref of |
1667 | operator definitions; each operator definition is a hashref with two |
1668 | entries: |
1669 | |
1670 | =over |
1671 | |
1672 | =item regex |
1673 | |
1674 | the regular expression to match the operator |
1675 | |
1676 | =item handler |
1677 | |
1678 | Either a coderef or a plain scalar method name. In both cases |
1679 | the expected return is C<< $sql >>. |
1680 | |
1681 | When supplied with a method name, it is simply called on the |
1682 | L<SQL::Abstract/> object as: |
1683 | |
1684 | $self->$method_name ($op, $arg) |
1685 | |
1686 | Where: |
1687 | |
1688 | $op is the part that matched the handler regex |
1689 | $arg is the RHS or argument of the operator |
1690 | |
1691 | When supplied with a coderef, it is called as: |
1692 | |
1693 | $coderef->($self, $op, $arg) |
1694 | |
1695 | |
1696 | =back |
1697 | |
1698 | |
32eab2da |
1699 | =head1 PERFORMANCE |
1700 | |
1701 | Thanks to some benchmarking by Mark Stosberg, it turns out that |
1702 | this module is many orders of magnitude faster than using C<DBIx::Abstract>. |
1703 | I must admit this wasn't an intentional design issue, but it's a |
1704 | byproduct of the fact that you get to control your C<DBI> handles |
1705 | yourself. |
1706 | |
1707 | To maximize performance, use a code snippet like the following: |
1708 | |
1709 | # prepare a statement handle using the first row |
1710 | # and then reuse it for the rest of the rows |
1711 | my($sth, $stmt); |
1712 | for my $href (@array_of_hashrefs) { |
1713 | $stmt ||= $sql->insert('table', $href); |
1714 | $sth ||= $dbh->prepare($stmt); |
1715 | $sth->execute($sql->values($href)); |
1716 | } |
1717 | |
1718 | The reason this works is because the keys in your C<$href> are sorted |
1719 | internally by B<SQL::Abstract>. Thus, as long as your data retains |
1720 | the same structure, you only have to generate the SQL the first time |
1721 | around. On subsequent queries, simply use the C<values> function provided |
1722 | by this module to return your values in the correct order. |
1723 | |
b864ba9b |
1724 | However this depends on the values having the same type - if, for |
1725 | example, the values of a where clause may either have values |
1726 | (resulting in sql of the form C<column = ?> with a single bind |
1727 | value), or alternatively the values might be C<undef> (resulting in |
1728 | sql of the form C<column IS NULL> with no bind value) then the |
1729 | caching technique suggested will not work. |
96449e8e |
1730 | |
32eab2da |
1731 | =head1 FORMBUILDER |
1732 | |
1733 | If you use my C<CGI::FormBuilder> module at all, you'll hopefully |
1734 | really like this part (I do, at least). Building up a complex query |
1735 | can be as simple as the following: |
1736 | |
1737 | #!/usr/bin/perl |
1738 | |
1739 | use CGI::FormBuilder; |
1740 | use SQL::Abstract; |
1741 | |
1742 | my $form = CGI::FormBuilder->new(...); |
1743 | my $sql = SQL::Abstract->new; |
1744 | |
1745 | if ($form->submitted) { |
1746 | my $field = $form->field; |
1747 | my $id = delete $field->{id}; |
1748 | my($stmt, @bind) = $sql->update('table', $field, {id => $id}); |
1749 | } |
1750 | |
1751 | Of course, you would still have to connect using C<DBI> to run the |
1752 | query, but the point is that if you make your form look like your |
1753 | table, the actual query script can be extremely simplistic. |
1754 | |
1755 | If you're B<REALLY> lazy (I am), check out C<HTML::QuickTable> for |
9d48860e |
1756 | a fast interface to returning and formatting data. I frequently |
32eab2da |
1757 | use these three modules together to write complex database query |
1758 | apps in under 50 lines. |
1759 | |
d8cc1792 |
1760 | =head1 REPO |
1761 | |
1762 | =over |
1763 | |
6d19fbf9 |
1764 | =item * gitweb: L<http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=dbsrgits/SQL-Abstract.git> |
d8cc1792 |
1765 | |
6d19fbf9 |
1766 | =item * git: L<git://git.shadowcat.co.uk/dbsrgits/SQL-Abstract.git> |
d8cc1792 |
1767 | |
1768 | =back |
32eab2da |
1769 | |
96449e8e |
1770 | =head1 CHANGES |
1771 | |
1772 | Version 1.50 was a major internal refactoring of C<SQL::Abstract>. |
1773 | Great care has been taken to preserve the I<published> behavior |
1774 | documented in previous versions in the 1.* family; however, |
9d48860e |
1775 | some features that were previously undocumented, or behaved |
96449e8e |
1776 | differently from the documentation, had to be changed in order |
1777 | to clarify the semantics. Hence, client code that was relying |
9d48860e |
1778 | on some dark areas of C<SQL::Abstract> v1.* |
96449e8e |
1779 | B<might behave differently> in v1.50. |
32eab2da |
1780 | |
d2a8fe1a |
1781 | The main changes are : |
1782 | |
96449e8e |
1783 | =over |
32eab2da |
1784 | |
9d48860e |
1785 | =item * |
32eab2da |
1786 | |
96449e8e |
1787 | support for literal SQL through the C<< \ [$sql, bind] >> syntax. |
1788 | |
1789 | =item * |
1790 | |
145fbfc8 |
1791 | support for the { operator => \"..." } construct (to embed literal SQL) |
1792 | |
1793 | =item * |
1794 | |
9c37b9c0 |
1795 | support for the { operator => \["...", @bind] } construct (to embed literal SQL with bind values) |
1796 | |
1797 | =item * |
1798 | |
96449e8e |
1799 | optional support for L<array datatypes|/"Inserting and Updating Arrays"> |
1800 | |
9d48860e |
1801 | =item * |
96449e8e |
1802 | |
1803 | defensive programming : check arguments |
1804 | |
1805 | =item * |
1806 | |
1807 | fixed bug with global logic, which was previously implemented |
7cac25e6 |
1808 | through global variables yielding side-effects. Prior versions would |
96449e8e |
1809 | interpret C<< [ {cond1, cond2}, [cond3, cond4] ] >> |
1810 | as C<< "(cond1 AND cond2) OR (cond3 AND cond4)" >>. |
1811 | Now this is interpreted |
1812 | as C<< "(cond1 AND cond2) OR (cond3 OR cond4)" >>. |
1813 | |
96449e8e |
1814 | |
1815 | =item * |
1816 | |
1817 | fixed semantics of _bindtype on array args |
1818 | |
9d48860e |
1819 | =item * |
96449e8e |
1820 | |
1821 | dropped the C<_anoncopy> of the %where tree. No longer necessary, |
1822 | we just avoid shifting arrays within that tree. |
1823 | |
1824 | =item * |
1825 | |
1826 | dropped the C<_modlogic> function |
1827 | |
1828 | =back |
32eab2da |
1829 | |
32eab2da |
1830 | =head1 ACKNOWLEDGEMENTS |
1831 | |
1832 | There are a number of individuals that have really helped out with |
1833 | this module. Unfortunately, most of them submitted bugs via CPAN |
1834 | so I have no idea who they are! But the people I do know are: |
1835 | |
9d48860e |
1836 | Ash Berlin (order_by hash term support) |
b643abe1 |
1837 | Matt Trout (DBIx::Class support) |
32eab2da |
1838 | Mark Stosberg (benchmarking) |
1839 | Chas Owens (initial "IN" operator support) |
1840 | Philip Collins (per-field SQL functions) |
1841 | Eric Kolve (hashref "AND" support) |
1842 | Mike Fragassi (enhancements to "BETWEEN" and "LIKE") |
1843 | Dan Kubb (support for "quote_char" and "name_sep") |
f5aab26e |
1844 | Guillermo Roditi (patch to cleanup "IN" and "BETWEEN", fix and tests for _order_by) |
48d9f5f8 |
1845 | Laurent Dami (internal refactoring, extensible list of special operators, literal SQL) |
dbdf7648 |
1846 | Norbert Buchmuller (support for literal SQL in hashpair, misc. fixes & tests) |
e96c510a |
1847 | Peter Rabbitson (rewrite of SQLA::Test, misc. fixes & tests) |
02288357 |
1848 | Oliver Charles (support for "RETURNING" after "INSERT") |
32eab2da |
1849 | |
1850 | Thanks! |
1851 | |
32eab2da |
1852 | =head1 SEE ALSO |
1853 | |
86298391 |
1854 | L<DBIx::Class>, L<DBIx::Abstract>, L<CGI::FormBuilder>, L<HTML::QuickTable>. |
32eab2da |
1855 | |
32eab2da |
1856 | =head1 AUTHOR |
1857 | |
b643abe1 |
1858 | Copyright (c) 2001-2007 Nathan Wiger <nwiger@cpan.org>. All Rights Reserved. |
1859 | |
1860 | This module is actively maintained by Matt Trout <mst@shadowcatsystems.co.uk> |
32eab2da |
1861 | |
abe72f94 |
1862 | For support, your best bet is to try the C<DBIx::Class> users mailing list. |
1863 | While not an official support venue, C<DBIx::Class> makes heavy use of |
1864 | C<SQL::Abstract>, and as such list members there are very familiar with |
1865 | how to create queries. |
1866 | |
0d067ded |
1867 | =head1 LICENSE |
1868 | |
d988ab87 |
1869 | This module is free software; you may copy this under the same |
1870 | terms as perl itself (either the GNU General Public License or |
1871 | the Artistic License) |
32eab2da |
1872 | |
1873 | =cut |
1874 | |